Anti-Cancer Activity of Lobaric Acid and Lobarstin Extracted from the Antarctic Lichen Stereocaulon alpnum

Abstract

Lobaric acid and lobarstin, secondary metabolites derived from the antarctic lichen Stereocaulon alpnum, exert various biological activities, including antitumor, anti-proliferation, anti-inflammation, and antioxidant activities. However, the underlying mechanisms of these effects have not yet been elucidated in human cervix adenocarcinoma and human colon carcinoma. In the present study, we evaluated the anticancer effects of lobaric acid and lobarstin on human cervix adenocarcinoma HeLa cells and colon carcinoma HCT116 cells. We show that the proliferation of Hela and HCT116 cells treated with lobaric acid and lobarstin significantly decreased in a dose- and time-dependent manner. Using flow cytometry analysis, we observed that the treatment with these compounds resulted in significant apoptosis in both cell lines, following cell cycle perturbation and arrest in G2/M phase. Furthermore, using immunoblot analysis, we investigated the expression of cell cycle and apoptosis-related marker genes and found a significant downregulation of the apoptosis regulator B-cell lymphoma 2 (Bcl-2) and upregulation of the cleaved form of the poly (ADP-ribose) polymerase (PARP), a DNA repair and apoptosis regulator. These results suggest that lobaric acid and lobarstin could significantly inhibit cell proliferation through cell cycle arrest and induction of apoptosis via the mitochondrial apoptotic pathway in cervix adenocarcinoma and colon carcinoma cells. Taken together, our data suggests that lobaric acid and lobarstin might be novel agents for clinical treatment of cervix adenocarcinoma and colon carcinoma.

Nitrogen-Fixing Bacteria Associated with Peltigera Cyanolichens and Cladonia Chlorolichens

“…Foliose lichens usually come into contact with the underlying substrate over a wider surface compared to fruticose lichens. It is probable that the difference in contact with their substrates affects the selection of bacteria that are associated with the thalli, which is performed through the production of metabolites and certain enzymatic activities [17,48] with antibiotic, cytotoxic, and antiviral effects [49,50,51,52,53,54]. These micro-environmental modifications (i.e., niche construction) could already shape the species interactions [55].…”

Carbon Consumption Patterns of Microbial Communities Associated with Peltigera Lichens from a Chilean Temperate Forest

“…Several studies have characterized the biologically active metabolites produced by lichens (e.g., antibiotic, antiviral, anti-inflammatory, analgesic, cytotoxic, etc.) [ 71 , 73 , 74 , 75 , 76 ]; however, fewer studies isolated microorganisms associated with lichens as bioresources of novel bioactive compounds with biotechnological applications [ 77 , 78 , 79 , 80 , 81 ]. Here we propose that metabolic profiling could be used as a preliminary approach to select suitable samples to isolate microorganisms with specific metabolic features.…”

Anticancer Potential of Lichens’ Secondary Metabolites

“…In regard to programmed cell death, lichens act as activators of apoptosis in various cancer cells [21,26] through the modulation of gene expression of products related to apoptosis such as caspases, p53, p38, or anti-/pro-apoptotic proteins of Bcl-2 family [29]. Induction of apoptosis by lichens might be associated also with an increase of cleaved PARP, a stress response protein repairing damaged DNA and regulating chromatin structure [30], with inactivation of the mammalian target of rapamycin (mTOR) or activation of c-Jun N-terminal kinase (JNK) signaling [27]. Anti-proliferative effects of lichens can be modulated through the regulation of other signaling pathways such as ERK1/2 and AKT [31] or proliferation protein marker Ki-67 [32].…”